Executable files that are built using dynamic linking do not contain library code from .so files. You might be making a typical mistake that the compiler knows about. This is useful for compile time checking, especially together with __builtin_constant_p and inline functions. And don't ignore warnings as you compile your code; warnings usually indicate a lurking problem that can lead to real problems later. this contact form
The linking process makes those connections, and that's were things can go wrong. –Kerrek SB Feb 18 '13 at 23:17 2 You're effectively asking the difference between "compiling" and "linking". The GCC attributes include (from the GCC 4.4.1 manual): error ("message") If this attribute is used on a function declaration and a call to such a function is not eliminated through Following is some output from make: .obj/ca_address.o(.gnu.linkonce.t._ZN10DataObject16getConstraintGroupEv+0x4): In function `DataObject::getConstraintGroup()': /usr/local/qt-x11-free-3.2.3/include/qshared.h:50: undefined reference to `DataObject::s_Cm' collect2: ld returned 1 exit status make: *** [hw7] Error 1 The compiler found the declaration, Note, also, that compiler errors will always include a line number at which the error was detected.
If you find it in a .cpp file, you must make sure that Both the .cpp and the .h file are mentioned in the project. A weird and spooky clock Output a googol copies of a string Missing Schengen entrance stamp Advisor professor asks for my dissertation research source-code How much more than my mortgage should I got an email notification, but for all others here that may help you, the thread is buried due to his age. If you leave out myClass.o, then it will not have the class definition even if you correctly included myClass.h!
However, if you manually compile and install libraries, it may be necessary for you to edit this file. I added more information in an edit. –jilles Jan 15 '11 at 18:12 add a comment| up vote 0 down vote One idea could be to generate a stub library that If you can't find it, how can the linker? Linker Error In C++ Undefined Symbol Linker errors mean the linker could not build an executable program from the object code you provided.
With a linker error, the problem is related to how your source code modules link together. Linker Error In Turbo C The problem is often that the variable is simply misspelled. I don't know what happens if an old binary has an unversioned reference, but it is probably sensible if there is only one definition. Save your draft before refreshing this page.Submit any pending changes before refreshing this page.
Executable files that are built using static linking contain all the library code needed to run. Compilation Error C++ Rate this: Please Sign up or sign in to vote. Therefore, ld will not find it, but rtld will find the versioned definition when an old binary is run. In turn, I'll first cover dealing with compiler errors and then with linker errors.
These errors often occur due to improper use of arrays or pointers. http://stackoverflow.com/questions/14947050/compiler-error-vs-linker-error Remember, you cannot generally assume variables get initialized to zero. How To Solve Linker Error In C If the configuration programs ignore the errors, they're simply broken. Linker Error In C Undefined Symbol If you recently added a Q_OBJECT macro to one of your existing headers, then re-run qmake, because the Makefile needs to be rebuilt!
Does that mean it worked? Get Jumping into C++ today! Popular pages Exactly how to get started with C++ (or C) today C Tutorial C++ Tutorial 5 ways you can learn to program faster The Now someone can give you pieces of line and you say, "looks alright". Permalink Posted 4-Oct-11 5:34am Mehdi Gholam326.4K Comments Simon Bang Terkildsen 4-Oct-11 13:23pm +5, completely agree if the OP is new to programming he/she should start with a managed Compilation Error In C
I don't know what they do to make that happen. c++ c compiler-construction linker share|improve this question asked Feb 18 '13 at 23:14 user997112 7,5411057136 closed as not constructive by 0x499602D2, Andy Prowl, billz, EJP, Graviton Feb 26 '13 at 4:03 Handling Cryptic or Bizarre Messages There are several types of compiler errors that are especially frustrating. This can be dangerous if you don't end up rewriting the right section of code, but it can be helpful.
ldd will list the name of each shared object file and the full path to its location. Compile Time Error In C Programming Linker errors are errors encountered when these dependencies are verified during the creation of a final object file. Although you don't want to ignore them, compiler warnings aren't something severe enough to actually keep your program from compiling.
While it is possible to leave the function undefined and thus invoke a link failure, when using this attribute the problem will be diagnosed earlier and with exact location of the external libraries). Finally, if nothing else works, you can always just rewrite a few lines of code to clear out any hidden syntax errors that might be hard for the eye to catch. Linker Error Undefined Reference To Even the first compiler error you get might be due to something several lines before the indicated warning.
Getting a link-time warning is tricky. For example, __asm__(".symver hidden_badfunc, [email protected]_1.0"); Normally, there would also be a default version, like __asm__(".symver new_badfunc, badfunc@@MYLIB_1.1"); or via a Solaris-compatible version script, but the trick is not to add one. functions, global variables), and will list information about them including if they are defined or not (defined in a .o means the code for this function or the declaration of this Here is some more information about make.
best to start at the top. Be careful that your compiler doesn't actually support these functions at all (this could happen if you include your own declaration of a function to get around a compile-time error).